Problem: Express your answer as a mixed number simplified to lowest terms. $20\dfrac{4}{9}-8\dfrac{8}{12} = {?}$
Answer: Simplify each fraction. $= {20\dfrac{4}{9}} - {8\dfrac{2}{3}}$ Find a common denominator for the fractions: $= {20\dfrac{4}{9}}-{8\dfrac{6}{9}}$ Convert ${20\dfrac{4}{9}}$ to ${19 + \dfrac{9}{9} + \dfrac{4}{9}}$ So the problem becomes: ${19\dfrac{13}{9}}-{8\dfrac{6}{9}}$ Separate the whole numbers from the fractional parts: $= {19} + {\dfrac{13}{9}} - {8} - {\dfrac{6}{9}}$ Bring the whole numbers together and the fractions together: $= {19} - {8} + {\dfrac{13}{9}} - {\dfrac{6}{9}}$ Subtract the whole numbers: $=11 + {\dfrac{13}{9}} - {\dfrac{6}{9}}$ Subtract the fractions: $= 11+\dfrac{7}{9}$ Combine the whole and fractional parts into a mixed number: $= 11\dfrac{7}{9}$